// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
 **********************************************************************
 *   Copyright (c) 2002, International Business Machines Corporation
 *   and others.  All Rights Reserved.
 **********************************************************************
 *   Date        Name        Description
 *   01/14/2002  aliu        Creation.
 **********************************************************************
 */

package com.ibm.icu.text;

/**
 * <code>UnicodeReplacer</code> defines a protocol for objects that replace a range of characters in
 * a Replaceable string with output text. The replacement is done via the Replaceable API so as to
 * preserve out-of-band data.
 *
 * @author Alan Liu
 */
interface UnicodeReplacer {

    /**
     * Replace characters in 'text' from 'start' to 'limit' with the output text of this object.
     * Update the 'cursor' parameter to give the cursor position and return the length of the
     * replacement text.
     *
     * @param text the text to be matched
     * @param start inclusive start index of text to be replaced
     * @param limit exclusive end index of text to be replaced; must be greater than or equal to
     *     start
     * @param cursor output parameter for the cursor position. Not all replacer objects will update
     *     this, but in a complete tree of replacer objects, representing the entire output side of
     *     a transliteration rule, at least one must update it.
     * @return the number of 16-bit code units in the text replacing the characters at offsets
     *     start..(limit-1) in text
     */
    public abstract int replace(Replaceable text, int start, int limit, int[] cursor);

    /**
     * Returns a string representation of this replacer. If the result of calling this function is
     * passed to the appropriate parser, typically TransliteratorParser, it will produce another
     * replacer that is equal to this one.
     *
     * @param escapeUnprintable if true then convert unprintable character to their hex escape
     *     representations, \\uxxxx or \\Uxxxxxxxx. Unprintable characters are defined by
     *     Utility.isUnprintable().
     */
    public abstract String toReplacerPattern(boolean escapeUnprintable);

    /**
     * Union the set of all characters that may output by this object into the given set.
     *
     * @param toUnionTo the set into which to union the output characters
     */
    public abstract void addReplacementSetTo(UnicodeSet toUnionTo);
}

// eof
